In hair cosmetics, film-forming polymers and oily components have been conventionally used as hair-setting agents for fixing and keeping hair styles. For example, as the film-forming polymers, various types of polymers, such as anionic, amphoteric, cationic, and nonionic polymers, have been used alone or in combination depending on the characteristics of products such as hair spray, hair mousse, color lotion, and hair gel. Although such film-forming polymers can impart excellent hair-setting properties to the products, the resulting films are hard, and feelings such as stiffness and squeakiness occur in some cases. In the oily components, although the hair-setting properties are not high compared to those of the film-forming polymers, since no films are formed, the hardness and stiffness are low. In addition, the oily components have effect of providing gloss and have been therefore widely used as useful hair-setting agents in, in particular, emulsifier-type hair cosmetics. In particular, solid oils are excellent in restoring the style of hair out of shape, a hair-rearranging property, and have been widely used in emulsifier-type hair dressings (e.g., see Patent Documents 1 to 3).
Thus, technologies of formulating hair cosmetics excellent not only in the hair-setting property but also in the hair-rearranging property have been actively investigated in recent years. For example, a technology of combining qualitative and quantitative characteristics of film-forming polymers is known (e.g., see Patent Documents 4 and 5).
Furthermore, in addition to the combination of existing components, components that further add values to products have been also developed. For example, since (meth)acrylic polymer is transparent and it forms a film and has good workability, it has been widely used as a coating material, an adhesive material, a material for ink, a material for external use on skin, a cosmetic material, etc. However, since (meth)acrylic polymer has high polarity, it has also had many problems. As such, various copolymers have been developed so far. Examples of the thus developed copolymers include: an acryl-silicone-based graft copolymer obtained by radical copolymerization of a dimethylpolysiloxane compound having a radically polymerizable group at one end of a molecular chain thereof and a radically polymerizable monomer having acrylate and/or methacrylate as a main body (see for example, Patent Document 6); and an amphiphilic block copolymer comprising a polysiloxane block and a cationic block (see for example, Patent Document 7).